A spatially explicit height–diameter model for Scots pine in Estonia
By Matthias Schmidt, Andres Kiviste, Klaus von Gadow. European Journal of Forest Research, 2011
69 citations recorded by the source corpus.
This contribution presents an approach to model individual tree height–diameter relationships for Scots pine (Pinus sylvestris) in multi-size and mixed-species stands in Estonia using the Estonian Permanent Forest Research Plot Network. The dataset includes 22,347 trees. The main focus of the study was to use an approach that is spatially explicit allowing for high accuracy prediction from a minimum set of predictor variables that can be easily derived. Consequently, the height–diameter relationship is modeled as a function of only the stand quadratic mean diameter (dg) and the plot geographical coordinates. A specific generalized additive model gam is employed that allows for the integration of a varying coefficient term and 2-dimensional surface estimators representing a spatial trend and a spatially varying coefficient term. The high flexibility of the model is needed due to the very few predictor variables that subsume a variety of potential influential factors. Subsequently, a linear mixed model is used that quantifies the random variation between plots and between measurement occasions within plots, respectively. Hence, our model is based on the theory of structured additive regression models (Fahrmeir et al. 2007) and separates a structured (correlated) spatial effect from an unstructured (uncorrelated) spatial effect. Additionally, the linear mixed model allows for calibration of the model using height measurements as pre-information. Model bias is small, despite the somewhat irregular distribution of experimental areas within the country. The overall model shows some similarity with earlier applications in Finland. However, there are important differences involving the model form, the predictors and the method of parameter estimation.
Subfields: Environmental Engineering, Nature and Landscape Conservation
View Paper: https://www.semanticscholar.org/paper/819eeb6521b11d03d5d4d16dde0f8f2d58ae124e
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In Environmental Engineering
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Citations in the corpus
- Height–diameter equations for larch plantations in northern and northeastern China: a comparison of the mixed-effects, quantile regression and generalized additive models (2016, methodology): “D relationship (Zhang et al., 2008; Schmidt et al., 2011; Adamec and Drápela, 2015).”
- Modelling tree height–diameter relationships in multi-species and multi-layered forests: A large observational study from Northeast China (2014, background): “It has been proposed, for example, that variability in H–D within and among habitat types is adaptive or simply a passive response to an environmental gradient, such as light, elevation, slope, aspect or proximity to the coast (Schmidt et al., 2011).”
- Using quadratic mean diameter and relative spacing index to enhance height-diameter and crown ratio models fitted to longitudinal data (2016, unknown): “…has sometimes been modelled using only the d.b.h. as a single independent variable (Meyer, 1940; Richards, 1959; Burkhart and Strub, 1974; Stage, 1975; Bates and Watts, 1980; Wykoff et al., 1982; Ratkowsky and Giles, 1990; Schmidt et al., 2011; VanderSchaaf, 2014; Sharma and Breidenbach, 2015).”